Disposable surgical drapes made of nonwoven fabrics are in common use. Such drapes are generally supplied by manufacturers in a prefolded, wrapped, sterilized condition. It is important that the drape be wrapped and folded in such a manner that it can easily be unwrapped and unfolded without contaminating the portions of the drape which are desired to remain sterile during the operation. For a drape to be used to cover a patient during a surgical operation, one of the primary purposes of using the drape is to separate the nonsterile patient from the sterile operating personnel and equipment. Therefore, the bottom surface or patient side of the drape is not expected to remain sterile during the operation while the top surface or operation side of the drape is generally expected to remain sterile.
A very popular folding technique used for surgical drapes is fan folding in which forward and reverse folds are alternated. This technique is popular because the entire portion of the drape fan folded can be unfolded simply by grasping the edge of the top panel and pulling it away from the folded drape. Thus the drape can be unfolded with a minimum amount of handling and a corresponding minimum chance of contamination.
For a drape to be used to cover a patient, it is generally desirable to set the folded drape on the patient and to unfold the drape toward all sides with a minimum amount of handling and shifting of the position of the drape. In order to accomplish this, the exposed under side of the folded drape is generally a part of the bottom surface or patient side of the drape which is near the center of the drape; commonly it is designed to be positioned over the operation site of the patient. The folded drape is placed on the patient in the proper position and is then unfolded to all sides, thus covering the patient. Such drapes are generally folded such that the exposed outer surfaces of the folded drape are largely portions of the bottom surface of the drape.
It is very common to have a fenestration, i.e. an opening, in a drape. Since the fenestration generally corresponds to the site where surgery will take place, the fenestration is commonly exposed on the outside of the folded drape so that it can be positioned properly prior to unfolding the drape. This can pose a potential problem since the drape surface exposed through the fenestration is generally a portion of the top surface of the drape which must be maintained sterile; this is particularly true for fan folded drapes. This potential problem is often solved by placing a piece of paper covering the fenestration on the top side of the drape prior to folding the drape. When the drape is folded, the paper is exposed through the fenestration rather than a portion of the top surface of the drape; the paper is removed after the drape is unfolded.
A fenestrated drape as described above is often used for surgery on an extremity. It is usually desired to have the extremity extend through the fenstration so that it rests on the top surface of the unfolded drape. Often the extremity is covered by a separate drape while the remainder of the patient is covered by the fenestrated drape. For ease of placing the drape, it is common to have an extremity drape folded into two oppositely disposed, juxtaposed stacks of folds with their lowermost panels contiguous and the fenestration within the lowermost panels, such that the extremity can be extended through the fenestration and between the folded juxtaposed stacks of the drape prior to unfolding. In this situation, a protective paper inside the folded drape cannot be readily used unless it can be removed prior to unfolding the drape. For common folding patterns, especially fan folding into the stacks described above, the act of extending the extremity through the fenestration and between the folded stacks of the drape causes the extremity to contact and contaminate portions of the top surface of the drape which are exposed on the adjacent sides of the stacks of folds.
Extremity drapes of special design have been used to avoid the potential contamination which occurs when using a simple fenestrated drape. U.S. Pat. Nos. 3,910,268 issued on Oct. 7, 1975, to Miller and 3,926,185 issued on Dec. 16, 1975, to Krzewinski disclose split sheet drapes designed for extremity surgery which have extra flaps so that they can be placed around the extremity and overlapped to isolate the extremity to be operated on from the rest of the patient. U.S. Pat. No. 3,930,497 issued on Jan. 6, 1976, to Krebs also utilizes a split sheet so that it can be placed around the extremity; Krebs uses adhesive tapes along the split so that it can be secured in position around the extremity. U.S. Pat. No. 4,119,093 issued Oct. 10, 1978, to Goodman discloses a collapsible sock which is attached to the fenestration and into which the extremity is inserted, thus the extremity does not touch and contaminate the top side of the drape as it is inserted through the fenestration and the folded drape.